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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: SnapshotLevelDBKVStore.html 939 2015-05-29 01:16:17Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.kv.leveldb;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import org.iq80.leveldb.DB;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import org.iq80.leveldb.ReadOptions;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import org.iq80.leveldb.Snapshot;<a name="line.12"></a>
<span class="sourceLineNo">013</span>import org.jsimpledb.kv.CloseableKVStore;<a name="line.13"></a>
<span class="sourceLineNo">014</span>import org.slf4j.Logger;<a name="line.14"></a>
<span class="sourceLineNo">015</span>import org.slf4j.LoggerFactory;<a name="line.15"></a>
<span class="sourceLineNo">016</span><a name="line.16"></a>
<span class="sourceLineNo">017</span>/**<a name="line.17"></a>
<span class="sourceLineNo">018</span> * Read-only {@link LevelDBKVStore} based on a LevelDB {@link Snapshot}.<a name="line.18"></a>
<span class="sourceLineNo">019</span> *<a name="line.19"></a>
<span class="sourceLineNo">020</span> * &lt;p&gt;<a name="line.20"></a>
<span class="sourceLineNo">021</span> * This class ensures that the configured {@link Snapshot} is closed when this instance is closed.<a name="line.21"></a>
<span class="sourceLineNo">022</span> *<a name="line.22"></a>
<span class="sourceLineNo">023</span> * &lt;p&gt;<a name="line.23"></a>
<span class="sourceLineNo">024</span> * All mutation operations throw {@link UnsupportedOperationException}.<a name="line.24"></a>
<span class="sourceLineNo">025</span> */<a name="line.25"></a>
<span class="sourceLineNo">026</span>public class SnapshotLevelDBKVStore extends LevelDBKVStore implements CloseableKVStore {<a name="line.26"></a>
<span class="sourceLineNo">027</span><a name="line.27"></a>
<span class="sourceLineNo">028</span>    private final Logger log = LoggerFactory.getLogger(this.getClass());<a name="line.28"></a>
<span class="sourceLineNo">029</span>    private final Snapshot snapshot;<a name="line.29"></a>
<span class="sourceLineNo">030</span>    private boolean closed;<a name="line.30"></a>
<span class="sourceLineNo">031</span><a name="line.31"></a>
<span class="sourceLineNo">032</span>    /**<a name="line.32"></a>
<span class="sourceLineNo">033</span>     * Constructor.<a name="line.33"></a>
<span class="sourceLineNo">034</span>     *<a name="line.34"></a>
<span class="sourceLineNo">035</span>     * @param db LevelDB database to snapshot<a name="line.35"></a>
<span class="sourceLineNo">036</span>     * @param verifyChecksums whether to verify checksums on reads<a name="line.36"></a>
<span class="sourceLineNo">037</span>     */<a name="line.37"></a>
<span class="sourceLineNo">038</span>    public SnapshotLevelDBKVStore(DB db, boolean verifyChecksums) {<a name="line.38"></a>
<span class="sourceLineNo">039</span>        this(db, db.getSnapshot(), verifyChecksums);<a name="line.39"></a>
<span class="sourceLineNo">040</span>    }<a name="line.40"></a>
<span class="sourceLineNo">041</span><a name="line.41"></a>
<span class="sourceLineNo">042</span>    private SnapshotLevelDBKVStore(DB db, Snapshot snapshot, boolean verifyChecksums) {<a name="line.42"></a>
<span class="sourceLineNo">043</span>        super(db, new ReadOptions().snapshot(snapshot).verifyChecksums(verifyChecksums), null);<a name="line.43"></a>
<span class="sourceLineNo">044</span>        this.snapshot = snapshot;<a name="line.44"></a>
<span class="sourceLineNo">045</span>    }<a name="line.45"></a>
<span class="sourceLineNo">046</span><a name="line.46"></a>
<span class="sourceLineNo">047</span>    @Override<a name="line.47"></a>
<span class="sourceLineNo">048</span>    public synchronized void close() {<a name="line.48"></a>
<span class="sourceLineNo">049</span>        super.close();<a name="line.49"></a>
<span class="sourceLineNo">050</span>        if (this.closed)<a name="line.50"></a>
<span class="sourceLineNo">051</span>            return;<a name="line.51"></a>
<span class="sourceLineNo">052</span>        this.closed = true;<a name="line.52"></a>
<span class="sourceLineNo">053</span>        try {<a name="line.53"></a>
<span class="sourceLineNo">054</span>            this.snapshot.close();<a name="line.54"></a>
<span class="sourceLineNo">055</span>        } catch (Throwable e) {<a name="line.55"></a>
<span class="sourceLineNo">056</span>            this.log.error("caught exception closing LevelDB snapshot (ignoring)", e);<a name="line.56"></a>
<span class="sourceLineNo">057</span>        }<a name="line.57"></a>
<span class="sourceLineNo">058</span>    }<a name="line.58"></a>
<span class="sourceLineNo">059</span><a name="line.59"></a>
<span class="sourceLineNo">060</span>// KVStore<a name="line.60"></a>
<span class="sourceLineNo">061</span><a name="line.61"></a>
<span class="sourceLineNo">062</span>    @Override<a name="line.62"></a>
<span class="sourceLineNo">063</span>    public void put(byte[] key, byte[] value) {<a name="line.63"></a>
<span class="sourceLineNo">064</span>        throw new UnsupportedOperationException("KVStore is read-only");<a name="line.64"></a>
<span class="sourceLineNo">065</span>    }<a name="line.65"></a>
<span class="sourceLineNo">066</span><a name="line.66"></a>
<span class="sourceLineNo">067</span>    @Override<a name="line.67"></a>
<span class="sourceLineNo">068</span>    public void remove(byte[] key) {<a name="line.68"></a>
<span class="sourceLineNo">069</span>        throw new UnsupportedOperationException("KVStore is read-only");<a name="line.69"></a>
<span class="sourceLineNo">070</span>    }<a name="line.70"></a>
<span class="sourceLineNo">071</span><a name="line.71"></a>
<span class="sourceLineNo">072</span>    @Override<a name="line.72"></a>
<span class="sourceLineNo">073</span>    public void removeRange(byte[] minKey, byte[] maxKey) {<a name="line.73"></a>
<span class="sourceLineNo">074</span>        throw new UnsupportedOperationException("KVStore is read-only");<a name="line.74"></a>
<span class="sourceLineNo">075</span>    }<a name="line.75"></a>
<span class="sourceLineNo">076</span><a name="line.76"></a>
<span class="sourceLineNo">077</span>    @Override<a name="line.77"></a>
<span class="sourceLineNo">078</span>    public void adjustCounter(byte[] key, long amount) {<a name="line.78"></a>
<span class="sourceLineNo">079</span>        throw new UnsupportedOperationException("KVStore is read-only");<a name="line.79"></a>
<span class="sourceLineNo">080</span>    }<a name="line.80"></a>
<span class="sourceLineNo">081</span>}<a name="line.81"></a>
<span class="sourceLineNo">082</span><a name="line.82"></a>




























































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